Can't Use SPFileStream

I am trying to use SPFileStream but its not working. i am using following NameSpaces.

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.IO; 
using System.Net;
using System.ComponentModel;
using Microsoft.SharePoint.Client;
using SP = Microsoft.SharePoint.Client;
using Microsoft.SharePoint;